Fourstroke AMP LT 2024

The BMC Fourstroke AMP LT 2024 is a carbon downcountry eMTB built around the TQ HPR50 mid-drive and an integrated 360Wh battery. Headline numbers: 120mm travel front and rear, 50Nm and 300W peak from a 1.85kg motor, 17.19kg claimed on the base trim (15.9kg on the LTD), 66.5 degree head angle and reach climbing 437 to 496mm across S to XL. From EUR 6,699 on the THREE to EUR 7,499 base, with three trims above. The forum verdict, as @CJaMTB puts it, is "an unapologetic downcountry bike through and through" that brings race-bike geometry into the SL category.

Drive system and range. The TQ HPR50 is the lightest of the credible SL motors at 1.85kg and trades torque for silence, a magnetic noise floor and a 4kg total system penalty. It is rated 250W with a 300W peak and 50Nm. The 360Wh battery is integrated into the downtube and not removable, but an optional 160Wh range extender pushes the package toward 520Wh total. On a Small there is room for either a 750ml bottle or the extender, but not both, as @CJaMTB notes. Press testing puts a single charge at roughly two to three hours of mixed trail riding, and @CJaMTB reports it running shoulder to shoulder with a Trek Fuel EXe on the same motor.

Geometry and handling. 66.5 degrees up front is steep by trail eMTB standards but right for the downcountry brief, where pedalling efficiency and steering precision matter more than bombing wide-open descents. Reach steps cleanly: 437, 457, 476 and 496mm across S to XL. Chainstays are a uniform 435mm and wheelbase tops out at 1206mm on XL, which keeps the bike whippy on tight singletrack. @alenzghr contrasts the package against an Orbea Rise SL: half the battery, less travel, but roughly 3.5kg lighter and dramatically more XC.

Build and value. The trim ladder runs THREE (EUR 6,699), TWO, ONE, base (EUR 7,499) and the range-topping LTD at 15.9kg. THREE is the value sweet spot: @CJaMTB reports the stock RockShox SID 3P fork and SIDLUXE 3P Select+ shock as "supple and poppy with good pedal mode" and capable on fast steep tech. Shimano SLX 12-speed is the entry drivetrain. Owners frequently upgrade: @CJaMTB's build runs SRAM GX/XX AXS mixed transmission, G2 Ultimate brakes on 180mm rotors, Race Face ERA 160mm cranks, a Reverb AXS dropper and Bontrager RSL carbon cockpit.

Community-verified strengths.

• Weight class win. @Julie_X1 confirms 36lb (16.3kg) in-shop measurement, putting LT in the lightest tier of XC/trail eMTBs.
• Suspension on a short-travel bike that actually works. @CJaMTB rates the SID 3P/SIDLUXE platform as capable beyond its travel numbers.
• Silent drivetrain. The TQ motor's magnetic gearing is rattle-free, which makes the bike feel like an analogue trail bike with extra legs.

Caveats and known gripes.

• 50Nm is not 85Nm. Riders coming off Bosch CX or Specialized 2.2 will find climbs measurably harder. This is by design but worth understanding.
• 360Wh integrated, non-removable battery. Range extender is essential for long days, and on Small you choose between extender or bidon.
• 120mm out back is the limit. Bigger hits force you off the pedals; this is a fast trail bike, not an enduro tool.
• Price entry point. EUR 6,699 for the THREE undercuts top trims but still buys a full-power Bosch CX bike with 750Wh elsewhere.

Verdict. The Fourstroke AMP LT is a precision instrument for riders who already love downcountry analogue bikes and want a quiet 4kg of assist to extend the day. @CJaMTB owns two SL bikes on HPR50 and finds them "more than enough" for big mountain days. Buyers needing 140mm+ travel, a removable battery or full-power shove should walk away. Production status: current.